analog input simulator

guy's

i am trying to learn / teach myself analog i/o . and i need a way to simulate an analog input .i have been told that you can wire the analog output to the analog input . will this damage anything on most cards ? right now i just have a 0-10 volt analog in card . i have seen peanple make simulators from potentiometers . but i need to know the size / value and how it is wired . did not seen to find anything on the net ? can anyone help ?

thanks in advance

noob

Noob,

If your Analog Out has the same range (4-20 miliamp, or 0-10 VDC) then it would not do any damage to wire the output to the input.

What Input card do you have, and what brand and model of PLC?

Let's assume you have a 24 VDC supply available. Get a 10K pot and a 15 K resistor. Connect the 15K resistor to one leg of the pot. Connect the other side of the 15K resistor to DC+. Connect the other leg of the pot to DC-. Between the wiper of the pot and DC- you will be able to read from 0 to almost 10 volts. How close to 10 volts depends on the actual resistance of the pot and the resistor, and the actual voltage output of the DC supply.

The current across the resistor/pot combination will be 24 volts/25000 ohms, or approximately 1 milliamp. That's 0.025 watts. Just about any resistor and pot you're likely to locate will be able to handle that.

Consult the wiring diagram for the analog input module you're using to determine how to make the connection to your PLC.

Old SQD drives used to use a 2.5K pot.

Looks like you need to go back to school!
All you need is a suitable voltage divider on your input using two potentiometers vs two fixed resistors.

http://www.techlearner.com/DCPages/DCReseries.htm

Have fun learning.